Part 46 (1/2)
THE GREENLAND, OR POLAR ICE.
The following account of the Greenland, or Polar Ice, is abridged by the Editor of this work from a paper, by W. Scoresby, jun. M. W. S. published in The Memoirs of the Wernerian Natural-History Society:--
”Greenland is a country where every object is strikingly singular, or highly magnificent. The atmosphere, the land, and the ocean, each exhibit remarkable or sublime appearances.
”With regard to the atmosphere, several peculiarities may be noticed, viz.
its darkness of colour, and density; its frequent production of crystallized snow in a wonderful perfection and variety of form and texture; and its astonis.h.i.+ngly sudden changes from calm to storm, from fair weather to foul, and _vice versa_.
”The land is of itself a sublime object; its stupendous mountains rising by steep acclivities from the very margin of the ocean to an immense height, terminating in rigid, conical, or pyramidical summits; its surface, contrasting its native protruding dark-coloured rocks, with its burden of purest snow;--the whole viewed, under the density of a gloomy sky, forms a picture impressive and grand.
”Of the inanimate productions of Greenland, none perhaps excites so much interest and astonishment in a stranger, as the ice, in its great abundance and variety. The stupendous ma.s.ses known by the name of Ice Islands, Floating Mountains, or Icebergs, common to Davis' Straits, and sometimes met with here, from their height, various forms, and the depth of water in which they ground, are calculated to strike the beholder with wonder: yet the fields of ice, more peculiar to Greenland, are not less astonis.h.i.+ng. Their deficiency in elevation is sufficiently compensated by their amazing extent of surface. Some of them have been observed near 100 miles in length, and more than half that breadth; each consisting of a single sheet of ice, having its surface raised in general four or six feet above the level of the water, and its base depressed to the depth of nearly twenty feet beneath.”
The various kinds of Ice described.--”The ice in general is designated by a variety of appellations, distinguis.h.i.+ng it according to the size or number of pieces, their form of aggregation, thickness, transparency, &c.
I perhaps cannot better explain the terms in common acceptation amongst the whale-fishers, than by marking the disruption of a field. The thickest and strongest field cannot resist the power of a heavy swell; indeed, such are much less capable of bending without being dissevered, than the thinner ice, which is more pliable. When a field, by the set of the current, drives to the southward, and, being deserted by the loose ice, becomes exposed to the effects of a ground swell, it presently breaks into a great many pieces, few of which will exceed forty or fifty yards in diameter. Now, such a number of these pieces collected together in close contact, so that they cannot, from the top of the s.h.i.+p's mast, be seen over, are termed a _pack_.
”When the collection of pieces can be seen across, if it a.s.sume a circular or polygonal form, the name of _patch_ is applied, and it is called a _stream_ when its shape is more of an oblong, how narrow soever it may be, provided the continuity of the pieces is preserved.
”Pieces of very large dimensions, but smaller than fields, are denominated _floes_: thus, a field may be compared to a pack, and a floe to a patch, as far as regards their size and external form.
”Small pieces which break off, and are separated from the larger ma.s.ses by the effect of attrition are called _brash-ice_, and may be collected into streams or patches.
”Ice is said to be loose or open, when the pieces are so far separated as to allow a s.h.i.+p to sail freely amongst them: this has likewise been called _drift-ice_.
”A _hummock_ is a protuberance raised upon any plane of ice above the common level. It is frequently produced by pressure, where one piece is squeezed upon another, often set upon its edge, and in that position cemented by the frost. Hummocks are likewise formed by pieces of ice mutually crus.h.i.+ng each other, the wreck being heaped upon one or both of them. To hummocks, the ice is indebted for its variety of fanciful shapes, and its picturesque appearance. They occur in great numbers in heavy packs, on the edges, and occasionally in the middle of, fields and floes.
They often attain the height of thirty feet or upwards.
”A _calf_, is a portion of ice which has been depressed by the same means as a hummock is elevated. It is kept down by some larger ma.s.s, from beneath which it shews itself on one side. I have seen a calf so deep and broad, that the s.h.i.+p sailed over it without touching, when it might be observed on both sides of the vessel at the same time: this, however, is attended with considerable danger, and necessity alone warrants the experiment, as calves have not unfrequently (by a s.h.i.+p's touching them, or disturbing the sea near them) been called from their submarine situation to the surface, and with such an accelerated velocity, as to stave the planks and timbers of the s.h.i.+p, and in some instances to reduce the vessel to a wreck.
”Any part of the upper superficies of a piece of ice, which comes to be immersed beneath the surface of the water, obtains the name of a _tongue_.
”A _bight_ signifies a bay or sinuosity, on the border of any large ma.s.s or body of ice. It is supposed to be called bight, from the low word _bite_, to take in, or entrap; because, in this situation, s.h.i.+ps are sometimes so caught by a change of wind, that the ice cannot be cleared on either tack; and in some cases, a total loss has been the consequence.”
ON THE TREMENDOUS CONCUSSIONS OF FIELDS OF ICE.--The occasional rapid motion of fields, with the strange effects produced on any opposing substance, exhibited by such immense bodies, is one of the most striking objects this country presents, and is certainly the most terrific. They not unfrequently acquire a rotary movement, whereby the circ.u.mference attains a velocity of several miles per hour. A field, thus in motion, coming in contact with another at rest, or, more especially, with a contrary direction of movement, produces a dreadful shock. The consequences of a body of more than ten thousand millions of tons in weight, meeting with resistance when in motion, may be better conceived than expressed! The weaker field is crushed with an awful noise; sometimes the destruction is mutual: pieces of huge dimensions and weight are not unfrequently piled upon the top, to the height of twenty or thirty feet, whilst doubtless a proportionate quant.i.ty is depressed beneath. The view of these stupendous effects, in safety, exhibits a picture sublimely grand; but where there is danger of being overwhelmed, terror and dismay must be the predominant feelings. The whale-fishers at all times require unremitting vigilance to secure their safety, but scarcely in any situation so much, as when navigating amidst those fields: in foggy weather, they are particularly dangerous, as their motions cannot then be distinctly observed. It may easily be imagined, that the strongest s.h.i.+p can no more withstand the shock of two fields, than a sheet of paper can stop a musket-ball. Numbers of vessels, since the establishment of the fishery, have been thus destroyed; some have been thrown upon the ice, some have had their hulls completely torn open, and others have been buried beneath the heaped fragments of the ice.
ICEBERGS.--”The term _icebergs_ has commonly been applied to those immense bodies of ice situated on the land, 'filling the valleys between the high mountains,' and generally exhibiting a square perpendicular towards the sea. They recede backward inland to an extent never explored. Martin, Crantz, Phipps, and others, have described those wonders of nature, and all agree as to their manner of formation, in the congelation of the sleet and rains of summer, and of the acc.u.mulated snow, partly dissolved by the summer sun, which, on its decline, freezes to a transparent ice. They are as permanent as the rocks on which they rest: for although large portions may be frequently separated, yet the annual growth replaces the loss, and probably on the whole, produces a perpetual increase. I have seen those styled the _Seven Icebergs_, situated in the valleys of the north-west coast of Spitzbergen; their perpendicular front maybe about 300 feet in height, the green colour, and glistening surface of which, form a pleasing variety in prospect, with the magnificence of the encompa.s.sing snow-clad mountains, which, as they recede from the eye, seem to rise 'crag above crag,' in endless perspective.
[Ill.u.s.tration: ICEBERGS OF GREENLAND.--Page 526.]
[Ill.u.s.tration: ICEBERGS OF SPITZBERGEN.--Page 528.]
”Large pieces may be separated from those icebergs in the summer season, when they are particularly fragile, by their ponderous overhanging ma.s.ses overcoming the force of cohesion; or otherwise, by the powerful expansion of the water, filling any excavation or deep-seated cavity, when its dimensions are enlarged by freezing, thereby exerting a tremendous force, and bursting the whole asunder.
”Pieces thus or otherwise detached, are hurled into the sea with a dreadful crash: if they are received into deep water, they are liable to be drifted off the land, and, under the form of ice-islands, or ice-mountains, they likewise still retain their parent name of icebergs. I much question, however, if all the floating bergs seen in the seas west of Old Greenland, thus derive their origin, their number being so great, and their dimensions so vast.”
MAGNITUDE OF ICEBERGS.--”If all the floating islands of ice thus proceed from disruptions of the icebergs generated on the land, how is it that so few are met with in Greenland, and those comparatively so diminutive, whilst Baffin's Bay affords them so plentifully, and of such amazing size?
The largest I ever saw in Greenland, was about 1000 yards in circ.u.mference, nearly square, of a regular flat surface, twenty feet above the level of the sea; and as it was composed of the most dense kind of ice, it must have been 150 or 160 feet in thickness, and in weight about 2,000,000 of tons. But ma.s.ses have been repeatedly seen in Davis' Straits, nearly two miles in length, and one-third as broad, whose rugged mountain summits were reared with various spires to the height of more than 100 feet, whilst their base must have reached to the depth of 150 yards beneath the surface of the sea. Others, again, have been observed, possessing an even surface of five or six square miles in area, elevated thirty yards above the sea, and fairly run aground in water of 90 or 100 fathoms in depth; the weight of which must have been upwards of two thousand millions of tons.”